Secondary metabolites with anti-platelet aggregation activity from the insect Tenebrio molitor

Recently, researches for novel food and medicinal materials have focused on insect resources. Tenebrio molitor is an edible insect and recognized to have various biological properties, such as antimicrobial, anticancer, antidementia, and antihypertensive effects. The aim of this study was to identify previously unreported bioactive anti-platelet compounds from T. molitor larvae. Chemical investigation on the larvae resulted in the isolation of ten secondary metabolites. The structures of these entities were identified as cyclo(L-Val-L-Pro) (1), cyclo(L-Ala-L-Pro) (2), cyclo(L-Pro-L-Tyr) (3), cyclo(L-Phe-L-Tyr) (4), cyclo(Val-Tyr) (5), cyclo(Ala-Ile) (6), hydroxytyrosol (7), N-acetyldopamine (8), N-acetyltyramine (9), and oleracein E (10) based on spectroscopic data analysis. All the isolates were evaluated for anti-platelet aggregation properties by monitoring clotting time. Cyclo(L-Pro-L-Tyr) (3), hydroxytyrosol (7), and N-acetyltyramine (9) were shown to have platelet aggregation inhibitory activities. Collectively, these results show that compounds 3, 7, and 9 could serve as candidates and provide scaffolds for the development of new anti-platelet drugs.